RSS, or Really Simple Syndication as it is generally known, refers to a family of file formats that is used for web syndication. It is normally used to automatically deliver newly posted content from websites – including forums, blogs and news sites, among others - to its readers. However, RSS is also useful for other things aside from delivering written content thanks to “enclosures” or media attachments. Wherein in its most basic use, people who are subscribed to RSS feeds gets updates from their favorite websites, media enclosures to RSS feeds is like attachments in emails sent between people. Files are “enclosed” in RSS items and then automatically delivered to the RSS subscribers. These attachments could be an image, an audio file, a video, and even an application or program.

Examples of RSS feeds with enclosures are podcasts (spoken content), Vlogs (video), MP3 Blogs (music files), and appcasts (programs).
Podcasting is perhaps one of the most famous of the mentioned uses of RSS for content delivery. It is the method of distributing audio content by attaching audio files of spoken content to the RSS feed. Podcast’s popularity is helped in part by the very device on which the term was based – the iPod. Podcast is a combination of iPod and Broadcast.

In its early stages, podcasts allowed users of handheld audio players such as the iPod to automatically download spoken content from independent internet-radio talk show publishers to their computers, and then listen to them on their iPods at a later time. The capability to “postpone“ listening to your favorite radio talk shows proved to be a very attractive feature and soon became a huge success.
This new-found way of content delivery quickly evolved paving the way for additional multi-media file formats to be used as media enclosures. Image enclosures to RSS feeds opened a window of possibilities for sharing photos over the internet. Photo-sharing sites, such as Flickr, featured RSS feeds for people’s photos. Flickr’s RSS feed enabled people to subscribe to other peoples’ photo albums so that their favorite photographer’s latest shots or friend’s latest vacation pictures are automatically delivered to you as they are posted. Avid fans of online web comics also benefit from image enclosures to RSS. A reader can subscribe to a web comic’s RSS feed and daily updates are automatically delivered to the readers’ RSS syndicator of choice.
Video enclosures to RSS, on the other hand, gave rise to an evolution of a type of blog called the video blog, which is sometimes referred to as Vlogs. Video blogs uses videos as its primary content and is usually accompanied by a supporting text, image, or additional data to provide context to the content.

Vblogs are slowly rising in popularity in thanks again to the introduction of this time, video-capable iPod.
Appcasting is a type of RSS feed wherein there are attached executable programs to regularly deliver new versions of software programs. Appcasting, though not as mainstream as podcasting and video blogs, is important and very significant, especially for those in the IT industry.